The effects of time compression on feature discrimination as a function of age.

This study used 30 tape-recorded sentences taken from the Carrow Auditory Visual Abilities Test, then time-compressed by the Lexicon Varispeech II to 50%, in order to investigate age-related changes in auditory discrimination. Each sentence offers one or more phonemic contrasts (manner or place of articulation, voicing, frequency, or some combination). Overall group mean performance was not different between 6-yr-olds (N:14) vs 8-yr-olds (N:20), or between 10-yr-olds (N:16) vs 15 young adults, but the 2 older groups were each significantly better than each of the 2 younger groups. The ontogenetic progression of this auditory processing ability seems to mature in the early part of the second decade of life. Of 5 feature contrasts, only place of articulation was significantly more difficult, for all ages. Of 6 frequency contrasts, only that for high frequencies was significantly more difficult, for all groups, possibly due to an as yet undocumented damping of high frequencies by the time-compression apparatus.